In the attached image you can see what appears to be lint in the image in the upper left portion in the sky. I've been mirrorless cameras for over a year now and have noticed that the sensor is very hard to keep clean. I preformed a test using 2 mirrorless cameras and 2 cameras with mirrors. The camera specs were very similar, full frame with the same native resolutions. Each camera used a 300mm telephoto lens. Each camera was set up with aperture priority and an ISO of 400. The dust became noticeable at f-stops f16 and smaller on the mirrorless camera (f-16 thru f-32). The smaller the stop the more noticeable. The mirrored camera were free of any noticeable aberrations. Each lens was cleaned prior to the testing. The mirrorless camera sensors were cleaned according to the manufacturer instructions and then manually cleaned. All the cleaning did was move the aberrations around or even create new ones. Does the mirror protect the sensor in cameras with mirrors? Does the sensor in mirrorless cameras attract dust because of an electrical charge? Has anybody else noticed this issue on their mirrorless cameras? It is usually most noticeable in clear blue sky like the attachment.

Do you remove your lens after every shoot or leave it on the camera? I'm constantly changing lens and usually store the camera detached from the lens. I follow good practice when changing the lens: clean the body of the camera before removing the lens. Clean body and rear lens cap before attaching and never remove the lens unless in the proper environment. But no matter how careful you are, the sensor will evenually need cleaning. My problem is that I believe I'm just moving the goobers around when using a blower instead of removing them from the body. That is why I'm wondering if the sensor has an electrostatic charge that keeps attracting the dust. I live in a very dry desert environment, about 17% humidity. Maybe I'm overreacting. The manufacturer instructs to use f11 when checking for artifacts. I usually start seeing issues at f16 when testing. I usually shoot around f8 in full manual mode. But the attached pic was shoot at f8. Everytime I try to clean the sensor, it seems to just change the pattern I see.

I have been shooting mirrorless since circa 2009 and DSLR since about 2011. I take reference pics and I watch for sensor goobers. My experiences are that mirrorless requires less sensor cleaning. A lot less. My DSLRs require cleaning every 6m or a year at best. My mirrorless sensors have gone much longer. In fact I can’t remember having to clean a mirrorless sensor. And I watch for Goobers and I take reference pics. If they are there I will see them.

When changing lenses I obey good lens changing hygiene. And “cleaning at startup/shutdown” (all available options) is turned on.

My suspicion is that lens changing hygiene plays a bigger role with mirrorless tech than with DSLR tech. Given good lens changing hygiene a DSLR will spot up in 6m to a year. Given that same hygiene a mirrorless sensor will not spot up.

That’s my 2 cents and I back it up with years of experience. It works for me. YMMV.